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  • 12-23-2010, 02:37 PM
    nnunez

    Re: Does M5 rear sway bar help with turning the car

    If anyone is interested, I can make the Urethane bushings.

    If someone has dimensions and hardness that is.

    I work for a Polyurethane company and can make all kinds of trinkets.

    I will not charge for the part but only the shipping.

    2000 540i Sport in Houston, TX
  • 12-21-2010, 09:28 PM
    BG

    Update: installed M5 rear bar - nice

    Thanks to all of you for advice. I bought the 16.5 mm bar, links, and parts from Husker BMW, which has reasonable prices. I was going to install it myself, but I only have ramps and the ground was cold, so I let my mechanic do it. Result: less leaning in tight turns, no obvious harshness. So far, a nice upgrade.

    (2002 530i, 16-inch wheels, regular non-sport suspension, 5-sp.)
  • 12-07-2010, 09:12 PM
    jimlev

    When I replaced my sway bushings I did consider (m

    using PowerFlex bushings in the traction strut and wishbone but read a few posts back then (possibly yours) about the increase in road noise so I decided not to get them. Mine are still the original ones that came in the car, just hit 131K today.
  • 12-07-2010, 08:30 PM
    calemon

    Re: I know we have differing views on this, however (m

    BTW, I did notice, contrary to what I was told by several people, that my Powerflex bushings never squeaked either. I was pretty happy about that. My indy who put them on while doing other work in 2005 told me they'd be creaking like a pirate ship in 9 months or so and would need relube - they never did.

    Mine significantly increased NVH (mostly the tension strut bushings). The wishbone bushings crumbled at around 3.5 years of age. After working on some strange handling issues I replaced the front sway bushings with the original rubber that was on the car for 7 years and it significantly improved predictability. I'm just about to replace the tension strut bushings with OE rubber again to remove the NVH. They are the most sheltered of all the bushings from the elements (remember that they are forward and covered on the I6) but I think they are loosening up too.

    As Jim said, our experiences have differed. I probably won't bother with urethane again except maybe on a fair weather fun car. I will say that (other than the NVH) when I got my new shocks and bushings put in in 2005 it was pretty impressive when pushed really hard. I remember noticing braking in particular. I figure the stock (7 year old at the time) tension strut bushings deform significantly under heavy braking, cause toe out and reduce stability. With brand new Powerflex everything stayed straight and true.

  • 12-07-2010, 07:43 PM
    jimlev

    I know we have differing views on this, however (m

    The polyurethane bushings I used (only on my sway bars) haven't made more noise that I can detect.
    They are still in great condition after many years and about 80K miles, no squeaks either.
    If any of you want to stick with OEM rubber bushings for an M5 bar I would suggest you use the next size smaller. The rubber is so soft that the bigger M5 bar will fit it and be held tighter for less lean in the corners....just my 2.
  • 12-07-2010, 12:57 PM
    Craig in Canada

    Re: NEW QUESTION: Use rubber or urethane bushings?

    As far as I know, Powerflex doesn't make a 16.5mm application.

    Regardless, my recommendation (after using Powerflex everywhere on my E39 in 2005) is for OE rubber. In my experience and opinion, urethane doesn't add as much in a street-driven car as it tends to take away in the form of service life and increased NVH. That's just my opinion, though.

  • 12-07-2010, 12:35 PM
    BG

    NEW QUESTION: Use rubber or urethane bushings?

    Do you folks recommend using the stock rubber 16.5 mm bushings or the Powerflex urethane ones? Thanks!
  • 12-05-2010, 08:53 PM
    540sport

    Because then it would be called the factory bar.


    Vin
    98 540 Sport with everything & extra hots
    BMW CCA, Boston Chapter
    "The 540 is the head-case supermodel girlfriend..." Eric S.
    "The worst thing you could do with your money is save it." ~ Jackie Gleason
    If everything seems under control, you're just not going fast enough. Mario Andretti
    The United States is a nation of laws: poorly written and randomly enforced. - Frank Zappa



  • 12-05-2010, 12:29 PM
    Eurodavid

    Re: LOL, how U been Euro, got those side walls of (m)

    Jim,

    They still look ok, we are still getting snow here, but late last and today it is not sticking anymore, and is mixing with rain, so will have to wait for other bad weather the rest of the season.

    So far, I'm too afraid to go over, say, 40mph, with them on. I also won't allow any of the family in the car either (just in case). Figure it is better to be safe than sorry, as I remember the old days when if you were a broke, young kid trying to stretch a tire to last just a bit longer, you sometimes might end up feeling & hearing a slight thud from one of your wheels as a small chunk of the tread had torn loose ;-)

    Did you guys on the N.E. Coast get blasted with that really, really cold air and then snow we got over here? I kept missing the news for the USA. We had the mid-to-low teens, which is like: "come on!', as Belgium is by the ocean for crissakes and we aren't ever supposed to see/feel that kind of stuff. The past 5 years have been getting progressively weirder in terms of weather compared to the last 20 or so we've spent on & off here.

    I almost--key word: almost-- miss living in that dry, parched AZ desert sand hole we used to have a home in.

    Eurodavid

  • 12-05-2010, 08:57 AM
    jimlev

    LOL, how U been Euro, got those side walls of (m)

    your snows all cracked yet? My 0 miles Dunlop SP2000E spare has been in the trunk for the last 6+ years, looks brand new, probably will never put it on the car cuz it won't match up with my PS2's.
  • 12-05-2010, 08:36 AM
    Eurodavid

    aw, better advice: spank that......

    assssssssssss.

    Phooey-patooey with that little rear sway bar link nut Mr. Lev describes and having to mess with putting a little, thin wrench on it. Real men just focus on the front nut and ignore the rear one when removing the sway bar links.

    Why? Well, we just fire up our HFT Central Pneumatic Earthquake 92353 wicked-fast 3/4" Impact Wrench with 1400 ft lbs of torque, hit the ignition button w/ reckless abandon, and BLAMMM-YOSEMITE-SAM!, it teleports that old link, nut and sometimes secured bolt right off there.

    Bit of husky man advice, though, when putting the new link and front nut back on: just use a really, really, REALLY light feather trigger finger, as if you were removing a contact from a baby's eye. Just like you are microscopic fleck of metal off your favorite sandwich, feather that trigger and BLAMMM, problem solved again. No screwing with flat, thin wrenches.




    This message has been brought to you by your unofficial trusty-dusty assss-spanking HFT rep:



    Eurodavid


    P.S. Stay tuned for next week's tutorial on how to use your Central Pneumatic Earthquake for removing those numerous pesky plastic-fender wheel-well screws...

  • 12-04-2010, 10:59 PM
    jimlev

    Just in case some of you didn't know....(m)

    When removing your old sway bar and install the new one you will need to put a thin wrench on the back side of the sway bar link (#6) to keep the stud from turning when you remove the (#7) nut.
    Push back the rubber boot just behind the sway bar and you will see the two flats for the wrench to fit on.

    http://www.realoem.com/bmw/showparts...17&hg=33&fg=45
  • 12-04-2010, 09:11 PM
    BG

    Excellent advice about M5 bar

    I will order one, too. It looks like a simple installation. And the price is reasonable.
  • 12-04-2010, 03:04 PM
    gregory528iT

    And, then who would buy an M5 if 540s

    handled as good as an M5?

    So it's a little of all above, a LOT of people do not want a stiffer handling car, it's safer for MOST people to have some understeer, and yeah if people only wanted M5 performance, no one would buy 525s, 530s, 540s etc..








    In MY bag.
    Taylor Made R7 TP 9.5, RE AX 75,
    Taylor Made Burner TP, 14.5
    Taylor Made Burner TP, 17.5
    Taylor Made R7 Steel 7W 21
    Titleist AP2s 4-PW, Dynamic Gold S300
    Titleist 54.14 Vokey Spin Mill SW
    Titleist 60.04 Vokey Spin Mill LW
    Oddessy "Dual Force 440" (bullseye with insert) putter, 34"
    Titleist ProV1


  • 12-04-2010, 06:44 AM
    calemon

    Re: Maybe do not understand understeer vs. over

    Understeer is the tendency for the car to want to continue going straight. It doesn't steer enough, thus understeers.

    Oversteer is the tendency for the car to want to spin. It steers too much, thus oversteers.

    One catch is that you don't want to confuse over/understeer with steering response or turn in response. Your car can understeer but still respond immediately to steering input. If you haven't modified your BMW, it probably still understeers - badly - but the tires and steering system respond much more quickly than on your 80s domestic car. Shocking, I know :)

    Further, there are still a lot of handling dynamics at play such as effective mass transfer depending on what else you're doing with the controls. If you do the right (wrong?) things, you can get a motorhome to oversteer and spin. Usually this involves anything which unsettles the chassis and makes the rear end light by either lifting from the throttle or stabbing at the brakes.

    *THIS* is why engineers design so much understeer into a car. What do people do when a deer jumps out in front of them on the highway on a rainy night? Hit the brakes (lighten the rear) and yank at the wheel (unsettle the chassis) then yank it another direction (spin city).

    These principles are another reason why people can spin if they go too fast on an onramp or similar. They start exceeding the traction limits (front or rear), they panic and lift suddenly off the throttle or hit the brakes (lightening the rear) and now they're still going too fast with a light rear - spin. When performance driving like on the track you can counteract the onset of slight oversteer by counter steering and gently applying slightly MORE throttle to transfer effective mass to the rear and increase grip for the lateral needs. There's a phrase "keep your foot in it" and it is not a natural reaction to go faster when you're going too fast. Understeer is how people think - if I'm going too fast I won't make the turn, I will need to slow down. If you're understeering and you lift to go for the brakes you may not save yourself, the tires only have so much grip, but at least the mass transfer won't make things worse.

    Knowing this and actually doing it when you're caught by surprise are two different things. If you don't have muscle memory from training and track time, many will probably still do the wrong thing. Your mind simply isn't in "racing" mode when you're driving back from the theatre or heading for groceries. I have an OK amount of training but not the seat time I'd like to have. I always worry that I'll react in the wrong way even though I 'know better' if I was asked to describe what one should do in a given situation.

    Increasing the size of your rear bar makes the car more neutral, but also puts you slightly more at risk of some of the above situations. The M5 rear bar still doesn't dial out all of the understeer from the E39 and I specifically mentioned my emergency avoidance moves to cite the fact that it doesn't suddenly become a spin-master. I will point out that I didn't touch the brakes during my one particularly wicked incident - there was no time and luckily my slow-mo brain knew not to under the circumstances. It was just like a movie - "Oh sh%*@!" and everything went to 1/4 speed for me, giving me time to think and react. Lucky. It could have just as easily gone "omg! *crunch*"

  • 12-03-2010, 08:59 PM
    BG

    Maybe do not understand understeer vs. over

    Possibly one of you can explain the issue of understeer versus neutral handling. I think I understand what understeer is. When I drove some of the most grim US cars in the 1980s and 1990s, like the Corsica, I would turn the steering wheel and the blasted body ploughed ahead straight. I kept wondering when the lousy car would turn. In contrast, my 1981 320i turns instantly and precisely. Turn the wheel and the body responds immediately. My 2002 530i is in-between (but much closer to the 320i model than the Corsica model). Two questions:

    1. Wouldn't the safest car be the one where the driver's inputs to the steering wheel are immediate? Why do manufacturers want understeer? I just don't get it.

    2. Should I install the 16.5 mm bar in my 530i and will that make more neutral handling? It has the regular suspension with 16 inch wheels, Michelin tires.

    Thanks!
  • 12-03-2010, 08:50 PM
    pm179

    Awesome Craig, thanks ... I'm going for the M5 bar

    ... like you (and others) have said "a great no-brainer" upgrade ;-)

    Hey, it can't hurt right?Michael in MD

    2003 540i 6-speed
    Sterling Gray / Black
  • 12-03-2010, 08:20 PM
    calemon

    Re: +1, do it, you won't be disappointed, and if you (

    The M5 bar is WAY more affordable than the Dinan bar and is only 0.5mm smaller. Like I said in my first post - no brainer.

    You don't actually have to be sliding at a drift angle to feel the bar and it's reduction of the understeer. Even while still fully planted you can feel the tendancy of the car to turn or not. It's not necessarily "flatter", it just turns better.

    I noticed a huge, immediate difference - very confidence inspiring and it felt like a mod giving me a real "advantage" on the road. Of course it's all blended in with the normal experience long ago but I can't imagine ever going back. The old bar is under my stairs just in case.

    Since putting on the bar I've done a couple of emergency avoidance reactions in addition to sporty driving. One avoidance was really serious - stuff that has never come loose in the trunk and cabin ever before (no matter how sporty I was driving) flew all over. I basically had to cross my arms at 55mph on a three-lane width of asphalt and not go into the ditch on the other side. No problems with unanticipated oversteer. I have the incident burned into my memory in slow mo - the car, tires, everything behaved perfectly. The front and rear both developed slip angles with the slip helping the rear to come around a bit when I had to counter steer. If I had anything but my summer tires on (Toyo T1R at the time) things would have turned out different. The moral of this paragraph is that the M5 bar didn't go "too far" and is a great complement to the handling.

  • 12-03-2010, 06:27 PM
    pm179

    Thanks all ... I won't drag it out ...I got it ;-)

    Michael in MD

    2003 540i 6-speed
    Sterling Gray / Black
  • 12-03-2010, 04:56 PM
    jimlev

    If it does it's minimal. Your front tires and (m)

    front suspension are responsible for steering and turn in response, the tires being the biggest contributor to quick response. Driving at the limit while cornering the bar may do something, but I doubt that most of us could tell the difference unless we measured the g force with both bars.
    It may be slightly more noticable on an I6 that on our V8's because they have rack and pinion steering and a lighter engine.
    This could turn into another "which oil is best" post..LOL
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